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Biomedical subjects

G Bellone

Publications and source records attributed to G Bellone.

At least 73 records · Page 4Linked to original sources
PubMed1986

Fc receptor triggering induces expression of surface activation antigens and release of platelet-activating factor in large granular lymphocytes.

Triggering of large granular lymphocyte (LGL) Fc receptor with a specific monoclonal antibody (AB8.28) linked to an insoluble matrix induces cell activation, as witnessed by expression of HLA class II (DR and DQ) molecules and interleukin 2 receptor. Moreover, this event is accompanied by a concomitant release of platelet-activating factor by LGL. We conclude that the Fc receptor molecule identified by mAb AB8.28 represents a trigger for LGL activation.

Antibodies, Monoclonal↗
PubMed1985

Effect of endothelial cell conditioned medium on the growth of human bone marrow fibroblasts.

Both endothelial cells (EC) and fibroblasts, two discrete populations of hemopoietic stroma, are known to modulate the proliferation and differentiation of hemopoietic progenitors. Recent reports also demonstrated that EC stimulate the in vitro growth of fibroblasts via a soluble factor. This finding seems to support the hypothesis that EC may play a role in the pathogenesis of bone marrow fibrosis in myeloproliferative disorders (MD). We have studied the effects of the conditioned medium (CM) from human umbilical vein EC cultures, obtained in serum free conditions, on the growth of bone marrow fibroblasts from normal donors and from patients with MD. The results show that EC derived CM contains a factor which stimulates the proliferation of fibroblasts and that can act as an authentic growth factor by inducing "quiescent" fibroblasts to proliferate. Moreover, we found that this endothelial derived growth factor (EDGF) equally promotes the proliferation of both normal and pathological progenitors of bone marrow fibroblasts (CFU-F) by increasing both the number and the size of the colonies.

Bone Marrow Cells↗
PubMed1985

Functional and molecular characterization by the CB04 monoclonal antibody of a cell surface structure exerting C3-complement receptor activity.

CB04 monoclonal antibody which reacts with an epitope of a surface molecule expressed on human monocytes has been elicited using peripheral blood lymphocytes as immunizer. The characterization of the monoclonal antibody examined at the phenotypic, molecular, and functional levels indicates that the CB04 antibody defines a structure present on monocytes, tissue macrophages, B cells, polymorphonucleates, and erythrocytes. The molecular weight (220 kD), the tissue distribution in health and disease conditions, and the involvement in relevant biological processes indicate that the CB04 structure is the receptor for the C3b fragment of the complement. The binding of the antibody to the cell surface induces inhibition of the C3bi receptorial function.

Animals↗
PubMed1985

Murine monoclonal antibodies as probes for the phenotypical, functional, and molecular analysis of a discrete peripheral blood lymphocyte population exerting natural killer activity in vitro.

Two monoclonal antibodies (AB8.28 and A10) reacting with large granular lymphocytes were extensively studied and characterized. The two peripheral blood lymphocyte subsets positive for the expression of AB8.28 and A10 determinants were isolated by cell sorting and the phenotype analyzed using a panel of anti-lymphocyte reagents. Both subsets displayed the characteristics of "null cells." Moreover, these subsets encompassed a significant amount of the natural killer activity, since preparations of peripheral blood lymphocytes deprived of AB8.28+ and A10+ cells showed a remarkable reduction of such activity. The analysis of the distribution of the AB8.28 and A10 epitopes has been carried out using a variety of cells, i.e., normal tissues, tumor cells, established cell lines, and preparations obtained from patients with different leukemic disorders. The structure bearing the epitopes recognized by the two monoclonal antibodies was characterized immunologically (immunoprecipitation, SDS-PAGE analysis, immunomodulation, and competition with other antibodies) and by various functional assays. On the basis of inhibition tests, the AB8.28 molecule seems to be related functionally and/or structurally with the IgG Fc receptor. By contrast, the A10 structure does not share this activity and so far has eluded any precise biological characterization.

Antibodies, Monoclonal↗
PubMed1984

[Cytological study of acid phosphatase activity of plasma cells in monoclonal gammopathies].

The activity of acid phosphatase in bone marrow plasma cells was investigated by a cytochemical method in 12 patients with multiple myeloma, in 12 patients with benign monoclonal gammopathy and in 5 normal controls. The activity of acid phosphatase was significantly higher in the multiple myeloma patients compared with the activity observed in controls and in benign monoclonal gammopathy patients (p less than 0.001). It is therefore suggested that this method may be a valuable adjunct in the differential diagnosis of monoclonal immunoglobulinemias .

Acid Phosphatase↗
PubMed1983

[Immunology of non-Hodgkin lymphomas].

Cytological and kinetic immunological homogeneity is typical of such lymphomas. Their cytogenesis is broadly connected to the development and differentiation of lymphocytes. It is mainly a question of proliferating B lymphocytes of which the monoclonal membrane receptors are tumoral markers. The final stage of B lymphocyte differentiation is the lymphoplasmacellular proliferation involving monoclonal Ig secretion and consequently the rarefaction and finally disappearance of surface receptors.

B-Lymphocytes↗
PubMed1978

[Sea-blue histiocytosis. Clinical and immunological study of a familial case].

This case (a young man) presented a clinical picture of a hard periorbital edema, hepatosplenomegaly and a mild bilateral pulmonary fibrosis. The histopatological pattern of our case (as well as his sister affected with the same syndrome) was characterized by the presence of macrophages full of blue staining granules and bone marrow macrophagic infiltrations. In the pulmonary function tests the volumes and compliance test and diffusing capacity were normal. The enzymatic deficit of the macrophage leads to the increase storage of phosphoglicerides and phosphosphingolipids responsibles for the blue staining with Wright-Giemsa stain. Our case fit into the specific pathology of the macrophage cell in accordance with the more recent views of the autonomy of the MPS (Mononuclear Phagocytic System). The known relationship between macrophages and T and B lymphocites have prompted us to study the cellular and humoral immunological behaviour of our case. We have observed an increased IgM immunoglobulins and an increase of IgM surface membrane receptors. Our results will be illustrated and compared with the until known 70 publicated cases.

Adult↗
PubMedDate not supplied

Peripheral-type benzodiazepine receptors and diazepam binding inhibitor-like immunoreactivity distribution in human peripheral blood mononuclear cells.

Peripheral-type benzodiazepine receptors (pBZr) in human lymphocytes have been detected only in mixtures of peripheral blood mononuclear cells (PBMC). The present investigation was designed to describe precisely the location of pBZr in the various sets and subsets of PBMC, purified using monoclonal antibodies to specific PBMC surface markers. Site densities and affinities of pBZr were measured in the intact cells by conventional binding, using 3H-PK 11195 as a ligand. Moreover, we used a specific radioimmunoassay to identify in these cells the presence of the polypeptide diazepam binding inhibitor (DBI), a putative endogenous ligand for various benzodiazepine receptors including the peripheral type. Two major findings are derived from these studies: first, the coexistence of pBZr and DBI, or closely related immunoreactive material, in all major lymphocyte sets and subsets, as well as in monocytes. And second, the significant correlation (r = 0.87, p < 0.001) observed between the density of pBZr in a given cell type and its abundance of DBI like-immunoreactivity (DBI-LI). For both pBZr and DBI-LI content the cell distribution was monocytes > B cells and large granular lymphocytes > T cells (CD3+ set or CD4+ and CD8+ subsets) (ANOVA: pBZr: F = 114.11, p < 0.001; DBI-LI: F = 20.79, p < 0.001). The results are discussed in terms of the possibility that DBI and pBZr might share a relevant interaction in immunocompetent elements, thereby contributing to a new route of connection between the immune and the nervous systems.

B-Lymphocytes↗
PubMedDate not supplied

Independent and synergistic effect of interleukin-2 and prolactin on development of T- and NK-derived LAK effectors.

We have studied the effect of recombinant (r)-Prl on the in vitro-induced MHC-unrestricted cytotoxicity of NK and T cells. A 4-day treatment with r-Prl in serum-free medium enhanced the cytotoxicity of NK cells to the NK-susceptible cell lines K562 and U937, but did not induce de novo NK cytotoxicity in T lymphocytes. By contrast, development of cytotoxicity against the LAK-susceptible cell lines HL60, Jurkat, Daudi and Supt-1 occurred in both NK and T cells. The effect of r-Prl on NK cells was bi-phasic with peaks at 25 ng/ml (1.2 nM), the upper physiological level, and 200 ng/ml (9.6 nM). By contrast, LAK activation of T cells only occurred at the highest r-Prl concentration. In addition to its intrinsic stimulatory activity, r-Prl was also capable of modulating in a dose-dependent manner distinct stages of the IL2-driven LAK/T differentiation pathway. Physiological concentrations of r-Prl interacted with low doses r-IL2 to significantly enhance generation of NK- and T-LAK activities. By contrast, pathological concentrations had opposite effects on generation of optimal LAK response, depending on the kind of LAK progenitor. The T-derived LAK activity was reversibly inhibited at the effector level, while the mature NK-LAK cells were stimulated. These data confirm our previous findings of a co-operative effect of Prl and IL2 on NK cell proliferation and reinforce the view that the signals conveyed by the two factors may be functionally related.

Cell Differentiation↗